A true divided light window is very attractive and popular for use in homes, but is very expensive as individual panes of glass must be assembled into a window. Numerous simulated true divided lights have been provided such as represented in the Palmer U.S. Pat. No. 4,783,938, wherein an internal metal grid of muntin bars is positioned between the spaced apart panes of glass. The use of metal muntin bars causes several problems. Heat loss through the metal bars was prevented by using insulated spacers between the bars and the glass. The spacers then produced stress points in the window, and during very cold weather, breakage would occur as the panes contracted towards each other.
It is also difficult to shape the metal bars as desired to produce the more complicated grid designs including numerous curved shapes. Rattling can also be a problem with metal internal muntin bars.
What is needed then is an authentic looking internal muntin bar grid which does not have the shortcomings of the metal internal muntin bars.